Basket catheter with balloon

ABSTRACT

In one embodiment, a catheter apparatus is configured to be inserted into a body part of a living subject, and including an elongated deflectable element including a distal end, an expandable basket assembly disposed at the distal end and comprising a plurality of splines and a plurality of electrodes disposed on the splines, an irrigation channel disposed in the elongated deflectable element, and an inflatable balloon disposed in the expandable basket assembly and including a plurality of irrigation holes in fluid connection with the irrigation channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patent application Ser. No. 17/068,395, filed Oct. 12, 2020. The entire contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to medical devices, and in particular, but not exclusively to, catheters.

BACKGROUND

A wide range of medical procedures involve placing probes, such as catheters, within a patient's body. Location sensing systems have been developed for tracking such probes. Magnetic location sensing is one of the methods known in the art. In magnetic location sensing, magnetic field generators are typically placed at known locations external to the patient. A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields, which are processed to determine the coordinate locations of the distal end of the probe. These methods and systems are described in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, in PCT International Publication No. WO 1996/005768, and in U.S. Patent Application Publications Nos. 2002/006455 and 2003/0120150 and 2004/0068178. Locations may also be tracked using impedance or current based systems.

One medical procedure in which these types of probes or catheters have proved extremely useful is in the treatment of cardiac arrhythmias. Cardiac arrhythmias and atrial fibrillation in particular, persist as common and dangerous medical ailments, especially in the aging population.

Diagnosis and treatment of cardiac arrhythmias include mapping the electrical properties of heart tissue, especially the endocardium, and selectively ablating cardiac tissue by application of energy. Such ablation can cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions. Various energy delivery modalities have been disclosed for forming lesions, and include use of microwave, laser and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall. In a two-step procedure, mapping followed by ablation, electrical activity at points within the heart is typically sensed and measured by advancing a catheter containing one or more electrical sensors into the heart, and acquiring data at a multiplicity of points. These data are then utilized to select the endocardial target areas at which the ablation is to be performed.

Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity. In use, the electrode catheter is inserted into a major vein or artery, e.g., femoral vein, and then guided into the chamber of the heart of concern. A typical ablation procedure involves the insertion of a catheter having a one or more electrodes at its distal end into a heart chamber. A reference electrode may be provided, generally adhered to the skin of the patient or by means of a second catheter that is positioned in or near the heart. RF (radio frequency) current is applied between the catheter electrode(s) of the ablating catheter and an indifferent electrode (which may be one of the catheter electrodes), and current flows through the media between the electrodes, i.e., blood and tissue. The distribution of current may depend on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than the tissue. Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause cellular destruction in the cardiac tissue resulting in formation of a lesion within the cardiac tissue which is electrically non-conductive. In some applications, irreversible electroporation may be performed to ablate the tissue.

US Patent Publication 2019/0117301 of Steinke, et al., describes a catheter and catheter system for treatment of a blood vessel of a patient including an elongate flexible catheter body with a radially expandable structure. A plurality of electrodes or other electrosurgical energy delivery surfaces can radially engage material to be treated when the structure expands. A material detector near the distal end of the catheter body may measure circumferential material distribution, and a power source selectively energizes the electrodes to eccentrically treat of a body lumen.

U.S. Pat. No. 9,757,180 to Gelfand, et al., describes systems, devices, and methods for treating a patient having a sympathetically mediated disease associated at least in part with augmented peripheral chemoreflex or heightened sympathetic activation. The treatments include ablating one or more peripheral chemoreceptors or associated afferent nerves to reduce or remove afferent neural signals from the peripheral chemoreceptor.

U.S. Pat. No. 9,474,486 to Eliason, et al., describes an electrophysiology catheter including an elongated, deformable shaft having a proximal end and a distal end and a basket electrode assembly coupled to the distal end of the shaft. The basket electrode assembly has a proximal end and a distal end and is configured to assume a compressed state and an expanded state. The electrode assembly further includes one or more tubular splines having a plurality of electrodes disposed thereon and a plurality of conductors. Each of the plurality of conductors extends through the tubular spline from a corresponding one of the plurality of electrodes to the proximal end of the basket electrode assembly. The tubular splines are configured to assume a non-planar (e.g., a twisted or helical) shape in the expanded state.

U.S. Pat. No. 9,060,756 to Bencini, et al., describes a method of ablating body tissue including: (a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient's body, and inflating the inflatable balloon portion; (b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site; (c) ablating the body tissue by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature; (d) employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue; and (e) repeating (c) and (d) when it is determined that the ablating did not cause the desired electrical changes.

U.S. Pat. No. 10,362,952 to Basu, et al., describes a catheter for diagnosing and ablating tissue that has a stabilized spine electrode assembly. The stabilized spine electrode assembly has at least two spines secured to the catheter body at their proximal ends and at least one tether, secured between locations distal of the proximal ends of adjacent spines. The spines have a collapsed arrangement in which the spines are arranged generally along a longitudinal axis of the catheter body and an expanded arrangement in which at least a portion of each spine bows radially outwards from the longitudinal axis and the at least one tether exerts tension on the adjacent spines.

SUMMARY

There is provided in accordance with an embodiment of the present disclosure, a catheter apparatus configured to be inserted into a body part of a living subject, and including an elongated deflectable element including a distal end, an expandable basket assembly disposed at the distal end and including a plurality of splines and a plurality of electrodes disposed on the splines, an irrigation channel disposed in the elongated deflectable element, and an inflatable balloon disposed in the expandable basket assembly and including a plurality of irrigation holes in fluid connection with the irrigation channel.

Further in accordance with an embodiment of the present disclosure the splines are disposed circumferentially around the inflatable balloon.

Still further in accordance with an embodiment of the present disclosure the inflatable balloon is configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least thirty percent of an inner surface area of the splines facing the inflatable balloon.

Additionally, in accordance with an embodiment of the present disclosure each of the splines includes an inner surface and an outer surface, the electrodes being disposed on the inner and outer surface of respective ones of the splines.

Moreover in accordance with an embodiment of the present disclosure the inflatable balloon and the expandable basket assembly include a distal end, the apparatus further including a support element connected to the distal end of the inflatable balloon and the distal end of the expandable basket assembly configured to maintain the gap of at least one millimeter between the fully inflated balloon and at least thirty percent of the inner surface area of the splines facing the inflatable balloon.

Further in accordance with an embodiment of the present disclosure respective ones of the splines include Nitinol.

Still further in accordance with an embodiment of the present disclosure the electrodes of the respective splines include Nitinol.

Additionally, in accordance with an embodiment of the present disclosure respective ones of the splines include respective polymer flex circuits.

Moreover, in accordance with an embodiment of the present disclosure at least ninety percent of the electrodes are disposed in a region of the expandable basket assembly, at least ninety percent of the irrigation holes of the inflatable balloon being disposed more proximally or more distally to the region.

Further in accordance with an embodiment of the present disclosure the electrodes are disposed in a region of the expandable basket assembly, the irrigation holes of the inflatable balloon being disposed more proximally or more distally to the region.

There is also provided in accordance with another embodiment of the present disclosure, a catheter apparatus configured to be inserted into a body part of a living subject, and including an elongated deflectable element including a distal end, an expandable basket assembly disposed at the distal end and including a plurality of splines and a plurality of electrodes disposed on the splines, and an inflatable balloon disposed in the expandable basket assembly and configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least thirty percent of an inner surface area of the splines facing the inflatable balloon.

Still further in accordance with an embodiment of the present disclosure the splines are disposed circumferentially around the inflatable balloon.

Additionally, in accordance with an embodiment of the present disclosure each of the splines includes an inner surface and an outer surface, the electrodes being disposed on the inner and outer surface of respective ones of the splines.

Moreover in accordance with an embodiment of the present disclosure the inflatable balloon and the expandable basket assembly include a distal end, the apparatus further including a support element connected to the distal end of the inflatable balloon and the distal end of the expandable basket assembly configured to maintain the gap of at least one millimeter between the fully inflated balloon and at least thirty percent of the inner surface area of the splines facing the inflatable balloon.

Further in accordance with an embodiment of the present disclosure respective ones of the splines include Nitinol.

Still further in accordance with an embodiment of the present disclosure the electrodes of the respective splines include Nitinol.

Additionally, in accordance with an embodiment of the present disclosure respective ones of the splines include respective polymer flex circuits.

There is also provided in accordance with still another embodiment of the present disclosure, a medical system including a catheter configured to be inserted into a body part of a living subject, and including an elongated deflectable element including a distal end, an expandable basket assembly disposed at the distal end and including a plurality of splines and a plurality of electrodes disposed on the splines, and an inflatable balloon disposed in the expandable basket assembly, and an ablation power generator configured to be connected to the catheter, and apply an electrical signal to at least one of the electrodes to ablate a tissue of the body part.

Moreover, in accordance with an embodiment of the present disclosure the catheter includes an irrigation channel disposed in the elongated deflectable element, and wherein the inflatable balloon includes a plurality of irrigation holes in fluid connection with the irrigation channel.

Further in accordance with an embodiment of the present disclosure the inflatable balloon is configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least thirty percent of an inner surface area of the splines facing the inflatable balloon.

Still further in accordance with an embodiment of the present disclosure each of the splines includes an inner surface and an outer surface, the electrodes being disposed on the inner and outer surface of respective ones of the splines.

Additionally, in accordance with an embodiment of the present disclosure at least ninety percent of the electrodes are disposed in a region of the expandable basket assembly, at least ninety percent of the irrigation holes of the inflatable balloon being disposed more proximally or more distally to the region.

Moreover, in accordance with an embodiment of the present disclosure the electrodes are disposed in a region of the expandable basket assembly, the irrigation holes of the inflatable balloon being disposed more proximally or more distally to the region.

Further in accordance with an embodiment of the present disclosure the ablation power generator is configured to apply the electrical signal between ones of the electrodes to perform irreversible electroporation of the tissue of the body part.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood from the following detailed description, taken in conjunction with the drawings in which:

FIG. 1 is a schematic view of a medical system constructed and operative in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of a catheter constructed and operative in accordance with an embodiment of the present invention;

FIG. 3A is a cross-sectional view of the catheter of FIG. 2 along line A:A;

FIG. 3B is a cross-sectional view of an alternate embodiment of the device shown in FIG. 2 with a balloon uncoupled to distal end of the basket member;

FIG. 4 is a more detailed cross-sectional view of the catheter inside block A of FIG. 3A;

FIG. 5 is a more detailed cross-sectional view of the catheter inside block B of FIG. 3A; and

FIG. 6 is a cross-sectional view of a catheter constructed and operative in accordance with an alternative embodiment of the present invention.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

Irrigation is commonly used with catheters to provide cooling during medical procedures such as radio-frequency (RF) ablation, for example. One solution for providing irrigation in a basket-type catheter is to have an irrigation channel run through the catheter which terminates in the middle of the basket. Irrigation fluid may then be pumped through the irrigation channel to the distal end of the irrigation channel where the irrigation fluid exits and provides cooling to tissue in the region of the basket as well as diluting blood locally. However, the irrigation is not very well directed and although it may be sufficient for electroporation, which does not generate much heat, it is generally not sufficient to reduce heat created during RF ablation. Another problem encountered with basket catheters is that the basket needs to be in a collapsed or semi-collapsed form during insertion into the body and then deployed to its expanded form in a body cavity. The requirement to be able to collapse and expand the basket adds further complications to providing effective irrigation as an irrigation channel may interfere with the expansion and collapsing of the basket. An additional problem encountered with basket catheters (whether used for ablation or diagnosis) is that during use, it has been found that blood clots may be created within the basket and stagnate there.

Embodiments of the present invention, solve the above problems by providing a catheter with an expandable basket assembly including electrodes thereon, with an inflatable balloon installed in the expandable basket assembly. When deployed, the balloon is inflated in the expanded basket assembly and acts to displace blood from the interior of the basket assembly to prevent blood clots being created within the basket assembly. Additionally, the balloon may include irrigation holes through which irrigation fluid is pumped to cool the electrodes in use. The balloon enables strategically placing the irrigation holes with respect to the electrodes to enhance cooling during use.

In some embodiments, the fully inflated balloon touches the interior surface of the expanded basket assembly. When there is no, or little, gap between the fully inflated balloon and the interior surface of the expanded basket assembly, blood is prevented from entering the interior of the basket assembly thereby preventing blood clots. In other embodiments, there is a gap between the fully inflated balloon and the interior surface of the expanded balloon. When there is a gap, the electrodes may be irrigated more efficiently (depending on the irrigation and electrode configuration), and the inner surface of the basket may include electrodes thereby increasing the electrode surface area that can be used for ablation.

In some embodiments, the catheter includes an elongated deflectable element, and an expandable basket assembly disposed at the distal end of the deflectable element. The basket assembly includes splines and electrodes placed on the splines. The catheter includes an inflatable balloon disposed in the expandable basket assembly with the splines being disposed circumferentially around the inflatable balloon.

In some embodiments, at least some of the splines include Nitinol. In some embodiments, the electrodes of the respective splines include Nitinol. For example, Nitinol splines are selectively covered with an insulating cover to leave electrodes exposed, or the Nitinol splines are covered and windows are opened in the covers to reveal electrodes. In other embodiments, the splines include respective polymer flex circuits. The flex circuits may be supported using Nitinol supports running along at least a given length of each spline.

In some embodiments, the catheter includes an irrigation channel disposed in the elongated deflectable element, and the inflatable balloon includes irrigation holes in fluid connection with the irrigation channel. In some embodiments, the electrodes are disposed in a region of the expandable basket assembly, and the irrigation holes of the inflatable balloon (when the balloon is fully inflated) are disposed more proximally or more distally to the electrode region (when the basket is fully expanded).

In some embodiments, the catheter includes an irrigation channel disposed in the elongated deflectable element, and the inflatable balloon includes irrigation holes in fluid connection with the irrigation channel. In some embodiments, at least ninety percent of the electrodes are disposed in a region of the expandable basket assembly, and at least ninety percent of the irrigation holes of the inflatable balloon (when the balloon is fully inflated) are disposed more proximally or more distally to the electrode region (when the basket is fully expanded).

In other embodiments, the inflatable balloon does not include irrigation holes. In those embodiments, irrigation may optionally be performed using other methods.

In some embodiments, the inflatable balloon is configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least part (e.g., at least thirty percent) of an inner surface area of the splines (of the fully expanded basket assembly) facing the inflatable balloon. The balloon may optionally include irrigation holes. In some embodiments, a support element is connected to the distal end of the inflatable balloon and the distal end of the expandable basket assembly and maintains the gap between the fully inflated balloon and the splines of the fully expanded basket assembly. In some embodiments, when a gap is maintained, electrodes may be disposed on the inner and outer surface of each spline thereby increasing the electrode surface area for use in ablation. The electrode on the inner surface may be integral with, or connected to an electrode on the outer surface. In some embodiments, the fully inflated balloon touches the splines.

The system may include an ablation power generator connected to the catheter, and applies an electrical signal to the electrode(s) to ablate tissue of the body part. In some embodiments, the ablation power generator applies an electrical signal between the electrodes to perform irreversible electroporation of tissue of the body part.

System Description

Reference is now made to FIG. 1 , which is a schematic view of a medical system 20 constructed and operative in accordance with an embodiment of the present invention. The system 20 includes a catheter 40 configured to be inserted into a body part of a living subject (e.g., a patient 28). A physician 30 navigates the catheter 40 (for example, a basket catheter produced Biosense Webster, Inc. of Irvine, CA, USA), to a target location in a heart 26 of the patient 28, by manipulating an elongated deflectable element 22 of the catheter 40, using a manipulator 32 near a proximal end of the catheter 40, and/or deflection from a sheath 23. In the pictured embodiment, physician 30 uses catheter 40 to perform electro-anatomical mapping of a cardiac chamber and ablation of cardiac tissue.

Catheter 40 includes an expandable basket assembly 35, which is inserted in a folded configuration, through sheath 23, and only after the catheter 40 exits sheath 23 does the basket assembly 35 regain its intended functional shape. By containing basket assembly 35 in a folded configuration, sheath 23 also serves to minimize vascular trauma on its way to the target location.

Catheter 40 includes a plurality of electrodes 48 for sensing electrical activity and/or applying ablation power to ablate tissue of the body part. Catheter 40 may incorporate a magnetic sensor (not shown in FIG. 1 ) at the distal edge of deflectable element 22 (i.e., at the proximal edge of the basket assembly 35). Typically, although not necessarily, the magnetic sensor may be a Triple-Axis Sensor (TAS) or a Dual-Axis Sensor (DAS), or a SAS by way of example only, based for example on sizing considerations. A second magnetic sensor (not shown) may be included at any suitable position on the assembly 35. The second magnetic sensor may be a TAS, a DAS, or a SAS by way of example only, based for example on sizing considerations. The magnetic sensors and electrodes 48 disposed on the assembly 35 are connected by wires running through deflectable element 22 to various driver circuitries in a console 24.

In some embodiments, system 20 comprises a magnetic-sensing sub-system to estimate an ellipticity of the basket assembly 35 of catheter 40, as well as its elongation/retraction state, inside a cardiac chamber of heart 26 by estimating the elongation of the basket assembly 35 from the distance between the magnetic sensors. Patient 28 is placed in a magnetic field generated by a pad containing one or more magnetic field generator coils 42, which are driven by a unit 43. The magnetic fields generated by coil(s) 42 transmit alternating magnetic fields into a region where the body-part is located. The transmitted alternating magnetic fields generate signals in the magnetic sensors, which are indicative of position and/or direction. The generated signals are transmitted to console 24 and become corresponding electrical inputs to processing circuitry 41.

The method of position and/or direction sensing using external magnetic fields and magnetic sensors, is implemented in various medical applications, for example, in the CARTO® system, produced by Biosense-Webster, and is described in detail in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, in PCT Patent Publication WO 96/05768, and in U.S. Patent Application Publications 2002/0065455 A1, 2003/0120150 A1 and 2004/0068178 A1.

Processing circuitry 41, typically part of a general-purpose computer, is further connected via a suitable front end and interface circuits 44, to receive signals from body surface-electrodes 49. Processing circuitry 41 is connected to body surface-electrodes 49 by wires running through a cable 39 to the chest of patient 28.

In an embodiment, processing circuitry 41 renders to a display 27, a representation 31 of at least a part of the catheter 40 and a mapped body-part, responsively to computed position coordinates of the catheter 40.

Processing circuitry 41 is typically programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory.

The medical system 20 may also include an ablation power generator 69 (such as an RF signal generator) configured to be connected to the catheter 40, and apply an electrical signal to the electrodes 48. The medical system 20 may also include an irrigation reservoir 71 configured to store irrigation fluid, and a pump 73 configured to be connected to the irrigation reservoir 71 and the catheter 40, and to pump the irrigation fluid from the irrigation reservoir 71 through an irrigation tube of the catheter 40 as described in more detail with reference to FIGS. 2, 3, and 5 .

The example illustration shown in FIG. 1 is chosen purely for the sake of conceptual clarity. FIG. 1 shows only elements related to the disclosed techniques for the sake of simplicity and clarity. System 20 typically comprises additional modules and elements that are not directly related to the disclosed techniques, and thus are intentionally omitted from FIG. 1 and from the corresponding description. The elements of system 20 and the methods described herein may be further applied, for example, to control an ablation of tissue of heart 26.

Reference is now made to FIG. 2 , which is a schematic view of the catheter 40 constructed and operative in accordance with an embodiment of the present invention.

The catheter 40 is configured to be inserted into a body part (e.g., the heart 26 (FIG. 1 )) of a living subject. The deflectable element 22 of the catheter 40 has a distal end 33. The deflectable element 22 may be produced from any suitable material, for example, polyurethane or polyether block amide. The assembly 35 is disposed distally to the deflectable element 22 and may be connected to the deflectable element 22 via a proximal coupling member 50 at the distal end 33. The proximal coupling member 50 typically comprises a hollow tube and may be formed from any suitable material, for example, but not limited to polycarbonate with or without glass filler, polyether ether ketone (PEEK) with or without glass filler, polyimide, polyamide, or Polyetherimide (PEI) with or without glass filler. The coupling member 50 may formed as an integral part of the deflectable element 22 or as part of the basket assembly 35 or as a separate element which connects with the deflectable element 22 and the basket assembly 35. As used herein, the term “distal” means that a referenced component is further away from the operator and “proximal” means that the referenced component is closer to the operator of the catheter.

The assembly 35 may include multiple splines 55 (only one labeled for the sake of simplicity), such as flexible strips with the electrodes 48 (only some labeled for the sake of simplicity) being disposed on the splines 55. In the embodiment of FIG. 2 , each spline 55 includes a single electrode 48. The assembly 35 may include any suitable number of electrodes 48 with multiple electrodes 48 per spline 55.

In some embodiments, at least some of the splines 55 include Nitinol. In some embodiments, the electrodes 48 of respective ones of the splines 55 include Nitinol. In other embodiments, respective ones of the splines 55 include respective polymer flex circuits. The flex circuits may be supported using Nitinol supports running along at least a length of each spline 55.

In the embodiment of FIG. 2 , each spline 55 is formed from Nitinol which is selectively covered with insulating material in the distal and proximal regions 57 (only some labeled for the sake of simplicity) of the splines 55 leaving a central region 59 (only some labeled for the sake of simplicity) of the splines 55 as an electrically active region to perform mapping and/or perform ablation or electroporation, by way of example. The structure of the assembly 35 may vary. For example, splines 55 (or other splines) may include flexible printed circuit boards (PCBs), or any suitable shape-memory alloy.

In some embodiments, the relaxed state of the basket assembly 35 is the expanded deployed form. The basket assembly 35 is configured to collapse into the collapsed form when the catheter 40 is retracted in a sheath 23 (FIG. 1 ) and is configured to expand to the expanded deployed form when the catheter 40 is removed from the sheath 23. The relaxed shape of the basket assembly 35 may be set by forming the splines 55 from any suitable resilient material such as Nitinol or PEI. In other embodiments, the relaxed state of the expandable basket assembly 35 is the collapsed form and the expandable basket assembly 35 is expanded by retracting a pulling element (e.g., puller wire) disposed in the length of the elongated deflectable element 22 and connected to the distal end of the expandable basket assembly 35.

The catheter 40 includes an inflatable balloon 65 disposed in the expandable basket assembly 35. The splines 55 are generally disposed circumferentially around the inflatable balloon 65. In the embodiment shown in FIG. 2 , the inflatable balloon 65 fully inflates so that it touches the splines 55 (along 90% or more of the length of each spline 55) of the fully expanded expandable basket assembly 35. In other embodiments, described in more detail with reference to FIG. 6 , there is a gap of at least 1 mm between the fully inflated balloon 65 and at least 30% of the inner surface area of the splines 55 of the fully expanded expandable basket assembly 35.

In some embodiments, the catheter 40 includes an irrigation channel 67 (shown in FIGS. 3A and 5 ) disposed in the elongated deflectable element 22. In the embodiment shown in FIG. 2 , the inflatable balloon 65 is shown including a plurality of irrigation holes 75. The irrigation holes 75 are in fluid connection with the irrigation channel 67 (FIG. 3A).

In some embodiments, the irrigation holes 75 are disposed in one or more regions of the inflatable balloon 65. In other embodiments, the irrigation holes 75 are disposed over the inflatable balloon 65. In some embodiments, the irrigation holes 75 are mainly disposed in regions of the inflatable balloon 65 which are not close to the electrodes 48. In some embodiments, the electrodes 48 are disposed in a given region of the expandable basket assembly 35, and the irrigation holes 75 of the inflatable balloon 65 are disposed more proximally or more distally (with respect to a plane perpendicular to the axis of the non-deflected catheter 40) to the given region when the inflatable balloon 65 and the expandable basket assembly 35 are fully expanded. In some embodiments, at least ninety percent of the electrodes 48 are disposed in a given region of the expandable basket assembly 35, and at least ninety percent of the irrigation holes 75 of the inflatable balloon 65 are disposed more proximally or more distally (with respect to a plane perpendicular to the axis of the non-deflected catheter 40) to the given region when the inflatable balloon 65 and the expandable basket assembly 35 are fully expanded.

In other embodiments, the inflatable balloon 65 does not include irrigation holes. In these embodiments, irrigation may optionally be performed using any suitable method.

The ablation power generator 69 (FIG. 1 ) is configured to be connected to the catheter 40, and apply an electrical signal to at least one of the electrodes 48 (e.g., between two or more of the electrodes 48 or between one or more of the electrodes 48 and a proximal electrode 77 disposed at the distal end of the elongated deflectable element 22 or with a reference electrode) to ablate tissue of the body part (e.g., heart 26). In some embodiments, the ablation power generator 69 is configured to apply the electrical signal between one or more of the electrodes 48 to perform irreversible electroporation of the tissue of the body part. The inflatable balloon 65 helps prevent the electrical signal from mainly conducting through the center of the expandable basket assembly 35 and instead enhances conduction of the electrical signal through the tissue of the body part.

The inflatable balloon 65 may include a biocompatible material, such as polyurethane, polyether block amide, silicone, nylon, or polyester. Typically, the balloon would have a wall thickness between 0.0005″ and 0.005″. The irrigation holes 75 may have any suitable diameter, for example, in the range of about 0.01 mm to 0.125 mm, e.g. 0.075 mm. The inflatable balloon 65 may include any suitable number of discrete holes 75, for example, between 1 and 200, e.g. 50. In some embodiments, irrigation holes 75 may include laser or mechanically drilled holes.

The pump 73 (FIG. 1 ) is configured to pump irrigation fluid from the irrigation reservoir 71 (FIG. 1 ) via the irrigation channel 67 (FIG. 3A) into the inflatable balloon 65 and through the irrigation holes 75. The irrigation fluid is used to inflate the inflatable balloon 65. In embodiments, where the inflatable balloon 65 does not include irrigation holes, the inflatable balloon 65 may be inflated with any suitable fluid, such as saline or a gas.

Reference is now made to FIG. 3A, which is a cross-sectional view of the catheter 40 of FIG. 2 along line A:A. FIG. 3A (inside block A) shows the distal ends of the inflatable balloon 65 and the splines 55 (only two labeled for the sake of simplicity) folded over and connected to a distal connector 85, which in some embodiments is a tube (e.g., polymer tube) or slug (e.g., polymer slug). The distal connector 85 is described in more detail with reference to FIG. 4 .

In some embodiments, the splines 55 and/or the inflatable balloon 65 may be connected to the distal connector 85 without being folded over so that when the basket assembly 35 is collapsed the splines 55 are approaching a flat formation along their length.

FIG. 3A (inside block B) shows that the proximal ends of the splines 55 are connected to the inner surface of the proximal coupling member 50. The proximal end of the inflatable balloon 65 is connected to a proximal connector 79 (for example, a polymer slug), which is secured to the proximal coupling member 50. The proximal connector 79 is described in more detail with reference to FIG. 5 . FIG. 3A also shows the irrigation channel 67 (which extends through the deflectable element 22, the proximal coupling member 50, and a slot 83 in the proximal connector 79), and a position sensor 81 (e.g., a magnetic position sensor).

In FIG. 3B, an alternate catheter end effector 40′ is shown which has a balloon 65′ arranged so that a distal balloon portion 65 a is not fixed or coupled to the catheter distal connector 85. That is, balloon 65′ has a free distal balloon portion 65 a (i.e., unconnected to distal connector 85) with the proximal balloon portion 65 b coupled to the proximal coupling member 50 so that the balloon 65′ is free to conform to the internal boundary of catheter splines 55. Balloon 65′ in FIG. 3B is different in those aspects as compared to balloon 65 in FIG. 3A.

Reference is now made to FIG. 4 , which is a more detailed cross-sectional view of the catheter 40 inside block A of FIG. 3A. The splines 55 are secured to the distal connector 85. The distal end of the inflatable balloon 65 is secured between the splines 55 and a distal securing ring 87. An adhesive or epoxy layer 89 is disposed between the distal securing ring 87 and the distal connector 85 securing the splines 55 and the inflatable balloon 65 in place. In some embodiments, the inflatable balloon 65 and the splines 55 may be secured between the distal connector 85 and distal securing ring 87 using a pressure fit and/or any suitable adhesive. The distal connector 85 and the distal securing ring 87 may be formed from any suitable material, for example, but not limited to polycarbonate with or without glass filler, PEEK with or without glass filler, or PEI with or without glass filler. The distal connector 85 also functions as a slug to plug the distal end of the inflatable balloon 65.

Reference is now made to FIG. 5 , which is a more detailed cross-sectional view of the catheter 40 inside block B of FIG. 3A or FIG. 3B.

FIG. 5 shows the proximal connector 79 and the slot 83. The slot 83 allows the irrigation channel 67-3 and electrical wires (e.g., for connection to one or more electrodes and/or sensors) to traverse the proximal connector 79. The irrigation channel 67-2 connects to the irrigation channel 67-3, which is narrower so that it fits in the slot 83. The inflatable balloon 65 is connected to the proximal connector 79, for example using adhesive. The inflatable balloon 65 may be connected to the proximal connector 79 using any suitable connection method.

The proximal ends of the splines 55 are secured between the proximal coupling member 50 and the position sensor 81 and the irrigation channel 67-2. The splines 55 may be secured to the proximal coupling member 50 using a pressure fit and/or any suitable adhesive. The irrigation channel 67-2 is connected to the irrigation channel 67-1, which is disposed in the elongated deflectable element 22.

The proximal connector 79 may be formed from any suitable material, for example, but not limited to polycarbonate with or without glass filler, PEEK with or without glass filler, or PEI with or without glass filler.

Reference is now made to FIG. 6 , which is a cross-sectional view of a catheter 100 constructed and operative in accordance with an alternative embodiment of the present invention. The catheter 100 is substantially the same as the catheter 40 of FIGS. 1-5 except for the following differences.

The catheter 100 includes an inflatable balloon 102, which is configured to fully inflate so that there is a gap 104 of at least one millimeter between the fully inflated balloon 102 and at least part (e.g., at least thirty percent) of an inner surface area of the splines 55 facing the inflatable balloon 102. The “inner surface” is defined as the surface of the splines 55 facing the inflatable balloon 102.

In some embodiments, the inflatable balloon 102 includes irrigation holes (not shown). In other embodiments, the inflatable balloon 102 does not include irrigation holes.

In some embodiments, the catheter 100 includes a support element such as the distal connector 85 connected to the distal end of the inflatable balloon 102 and the distal end of the expandable basket assembly 35 (and/or the proximal connector 79 connected to the proximal end of the inflatable balloon 102 and the proximal end of the expandable basket assembly 35) configured to maintain the gap 104 of at least one millimeter between the fully inflated balloon 102 and at least part (e.g., at least thirty percent) of the inner surface area of the splines 55 facing the inflatable balloon 102.

In some embodiments, the electrodes 48 are disposed on the inner and outer surface of respective ones of the splines 55. Using the inner and outer surfaces for the electrodes 48 provides a greater surface area for ablation. One of the electrodes 48 disposed on the inner surface of one of the splines 55 may be electrically connected to the corresponding electrode 48 on the outer surface of that spline 55. In some embodiments, a single electrode may extend from the inner surface to the outer surface (for example, when the spline 55 is formed from a conductor such as Nitinol).

As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 90%” may refer to the range of values from 72% to 108%.

Various features of the invention which are, for clarity, described in the contexts of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

The embodiments described above are cited by way of example, and the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. 

What is claimed is:
 1. A catheter apparatus, the apparatus comprising: an elongated deflectable element including a distal end that extends along a central longitudinal axis; an expandable basket assembly disposed proximate the distal end and comprising a plurality of splines extending from the distal end of the deflectable element to a distal spline connector and a plurality of electrodes disposed on the splines, each spline of the plurality of splines being affixed to another spline of the plurality of splines and to the distal spline connector at a distal end, the central longitudinal axis intersecting and passing through the distal spline connector; and an inflatable balloon disposed in the expandable basket assembly, the balloon including a proximal balloon portion coupled to the distal end and a freely uncoupled distal balloon portion proximate the distal spline connector.
 2. The apparatus according to claim 1, the splines being disposed circumferentially around the inflatable balloon.
 3. The apparatus according to claim 1, the inflatable balloon being configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least thirty percent of an inner surface area of the splines facing the inflatable balloon.
 4. The apparatus according to claim 3, each of the splines including an inner surface and an outer surface, the electrodes being disposed on the inner surface and the outer surface of respective ones of the splines.
 5. The apparatus according to claim 3, wherein the inflatable balloon and the expandable basket assembly include a distal end, the apparatus further comprising a support element connected to the distal end of the inflatable balloon and the distal end of the expandable basket assembly configured to maintain the gap of at least one millimeter between the fully inflated balloon and at least thirty percent of the inner surface area of the splines facing the inflatable balloon.
 6. The apparatus according to claim 1, each spline of the plurality of splines being affixed to the distal spline connector by an adhesive or epoxy layer.
 7. The apparatus according to claim 1, further comprising a distal securing ring surrounding the distal spline connector, each spline of the plurality of splines being secured between the distal spline connector and the distal securing ring to affix each spline of the plurality of splines to the distal spline connector.
 8. The apparatus according to claim 1, each distal end of the plurality of splines being folded over to be affixed to the distal spline connector.
 9. A catheter apparatus comprising: an elongated deflectable element including a distal end; an expandable basket assembly disposed at the distal end and comprising a plurality of splines and a plurality of electrodes disposed on the splines; an inflatable balloon disposed in the expandable basket assembly and configured to fully inflate so that there is a gap of at least one millimeter between the fully inflated balloon and at least thirty percent of an inner surface area of the splines facing the inflatable balloon; and a distal spline connector positioned at a distal end of the expandable basket and distal to the inflatable balloon, each spline of the plurality of splines being affixed to the distal spline connector at a distal end, the inflatable balloon being decoupled from the distal spline connector such that the inflatable balloon and the distal spline connector are configured to define a gap between the fully inflated balloon and the distal spline connector in addition to the gap between the fully inflated balloon and the splines.
 10. The apparatus according to claim 9, the splines being disposed circumferentially around the inflatable balloon.
 11. The apparatus according to claim 9, each of the splines including an inner surface and an outer surface, the electrodes being disposed on the inner surface and the outer surface of respective ones of the splines.
 12. The apparatus according to claim 9, the inflatable balloon and the expandable basket assembly including a distal end, the apparatus further comprising a support element connected to the distal end of the inflatable balloon and the distal end of the expandable basket assembly configured to maintain the gap of at least one millimeter between the fully inflated balloon and at least thirty percent of the inner surface area of the splines facing the inflatable balloon.
 13. The apparatus according to claim 9, respective ones of the splines including Nitinol.
 14. The apparatus according to claim 13, the electrodes of the respective splines including Nitinol.
 15. The apparatus according to claim 9, respective ones of the splines including respective polymer flex circuits.
 16. The apparatus according to claim 9, each spline of the plurality of splines being affixed to the distal spline connector by an adhesive or epoxy layer.
 17. The apparatus according to claim 9, further comprising a distal securing ring surrounding the distal spline connector, each spline of the plurality of splines being secured between the distal spline connector and the distal securing ring to affix each spline of the plurality of splines to the distal spline connector.
 18. The apparatus according to claim 9, each distal end of the plurality of splines being folded over to be affixed to the distal spline connector.
 19. The apparatus according to claim 9, the distal spline connector comprising a tube or a slug.
 20. A catheter apparatus comprising: an elongated deflectable element including a distal end; an expandable basket assembly disposed at the distal end and comprising a plurality of splines and a plurality of electrodes disposed on the splines; an inflatable balloon disposed in the expandable basket assembly; a distal spline connector positioned at a distal end of the expandable basket assembly; and a distal securing ring surrounding the distal spline connector, each spline of the plurality of splines being secured between the distal spline connector and the distal securing ring to affix each spline of the plurality of splines to the distal spline connector and the distal securing ring. 